To use Imageshack correctly, upload your image, scroll all the way down and click the 'Show Advanced Linking' button', ignore the warning that says "DO NOT Use Link Below when posting. Use FORUM Links above for posts" and copy the link below, then paste it into your post, then highlight the link in your post, then hit the Image button above the post box, or, click the Image button above the post box THEN paste the link between the img tags
Imageshack used correctly ^